Golang Global Variable Access

The problem of global variables in Golang.

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I ' m fairly new to Golang, this should is a simple answer but I ' ve tried searching every where with no luck.

How does I access a global variable that is declared/init in my main.go in a different. Go package/file? Keeps telling me, the variable is undefined (I-know that global variables was bad and this is just to be used as a Tim Estamp)

In Main.go

var StartTime = time.Now()func main(){...}

Trying to access StartTime in a different. go file but keep getting StartTime undefined

Variables Go global mainshareEditEditedJan ' at 13:51AskedJan ' at 13:36Nighthee18311

• 2 Possible Duplicate of Go build works fine but go run fails–ainar-g Jan "at 13:42"
• is the first letter of the variable name capitalized?–olif Jan ' at 13:43
• Yes, it is capitalized, and my go build fails–nighthee Jan "at 13:44
• is including all relevant files when is running the program ? That's, when running the code, was you running go run File1.go file2.go. Etc–olif Jan at 13:45
• Yes, to is more concise, I has a variable called ' var StartTime = time. Now () ' In my main.go if I try to access StartTime in a different. Go for the same directory, it says its undefined, W Ould I has to include "main" in the. go file, which im trying to call? –nighthee Jan at 13:47

Show 5More Comments2 Answersactiveoldestvotesup vote33down voteaccepted

I would "inject" the starttime variable instead, otherwise you have a circular dependency between the packages.

Main.go

var StartTime = time.Now()func main() { otherPackage.StartTime = StartTime}

Otherpackage.go

var StartTime time.Time

ShareEditEditedJan ' at 14:19answeredJan ' at 13:57Olif1,3301

• Yep It worked! thanks! –nighthee Jan at 14:34

Add a Commentup vote3down vote

I Create a file dif.go that contains your code:

package difimport ( "time")var StartTime = time.Now()

Outside the folder I create my main.go , it is ok!

package mainimport ( dif "./dif" "fmt")func main() { fmt.Println(dif.StartTime)}

Outputs:

2016-01-27 21:56:47.729019925 +0800 CST

Files directory structure:

folder  main.go  dif    dif.go

It works!

ShareEditEditedNov ' at 5:40Hi I ' m frogatto17.8k5 answeredJan ' at 14:02Joy Miao3

• My ' dif ' is a restful API and won ' t being called when the program starts but only if its invoked through URL, so I need To put the StartTime in Main.go and pass it to dif, you ' re passing it from dif to main, thanks for the try Though! –nighthee Jan at 14:05

Golang Global Variable Access